This invention relates to a system whereby an instrument, such as a grapple, can load or handle material when suspended from one point and the material can be transported while the instrument is suspended from a second point.
The development of the helicopter has been a boon to the transportation of materials from or to locations where access is otherwise difficult or impossible. One application of increasing importance involves the transportation of felled timber. In many areas, the readily accessible timber has all been harvested leaving highly desirable timber in difficult locations. One solution has been to use helicopters to transport the timber from the site where it is felled to a river or other available transportation means. Since the operation of a helicopter is a very expensive proposition, it is imperative that the aircraft be put to its most efficient use. It has been the practise to have ground crews assemble groups of logs in slings which are transported by a helicopter, suspending the sling from a fixed length cable. The cable should be suspended from a point generally in vertical alignment with the centre of gravity of the helicopter in order to avoid adverse effects on the operation and controls of the helicopter. When the helicopter arrives at its point of destination, the logs are deposited along with the cable. The efficient operation of the helicopter requires a fast turn about, and there is no time to stop and retrieve the cable. Consequently, large amounts of cable are accummulated at the destination point until transported back, for example by a second helicopter, to the point where trees are felled.